Scientists lighten up on dark energy

The universe is expanding at an accelerating rate because of ripples in space-time that stretch beyond the observable edges of the universe, according to a paper published in Physical Review Letters.

This theory runs counter to current scientific thinking, which holds that so-called dark energy is responsible for this phenomenon. No one has ever seen any dark energy, but scientists think that it acts as a kind of anti-gravity, forcing everthing in the universe away from everything else.

When Einstein first put his theories of relativity together, he included a cosmological constant, a number that accounted for this acceleration of the universe's expansion. He later referred to this as his greatest blunder, but his ideas have since been rehabilitated.

But now, Edward Kolb of the Fermi National Accelerator Laboratory says that Einstein "was right when he said he was wrong", according to a Reuters report.

Antonio Riotto at Italy's National Nuclear Physics Institute in Padova, who also worked on the research, told Reuters: "No mysterious dark energy is required. If dark energy were the size that theories predict ... it would have prevented the existence of everything we know in our cosmos."

Instead, he says, the acceleration is an after effect of the big bang that has not been properly accounted for.

However, the scientific community remains sceptical. Michael Turner from the University of Chicago actually coined the term "dark energy" and in 1990, co-authored a paper with Kolb. He says: "Their paper is going to get enormous scrutiny, and my own guess is that in the end, they'll be wrong."

"But they may get the last laugh. And the interesting thing is, if they get the last laugh, I doubt that this is the only effect of these long ripples. We may have to make some other changes." ®